Theoretical study of the thermally induced structural fluctuations in sub-nanometre size gold clusters
JM Cabrera-Trujillo and JM Montejano-Carrizales and F Aguilera-Granja and A Posada-Amarillas, EUROPEAN PHYSICAL JOURNAL D, 69, 167 (2015).
A reactive potential model and the classical molecular dynamics method (RMD) have been used to study the structure and energetics of sub- nanometre size gold clusters through well-known structural models reported in the literature for Au-N, with N = 19, 20 and 21 atoms. After several simulated-annealing simulations for temperatures up to 1500 K, the Au-N clusters clearly evolve to well-defined structures at room temperature. For the studied gold clusters, the low-lying structures are single-and double-icosahedra with mobile atoms on the surface, in agreement with experimental results on sub-nanometre size gold clusters exhibiting shape oscillations at room temperature and also with those involved in the design of molecules based on gold superatoms J.-I. Nishigaki, K. Koyasu, T. Tsukuda, Chem. Rec. 14, 897 (2014). The evolution of the structural stability of the Au-N clusters under exceptional thermal conditions is analysed by comparing the size and temperature variations of the centrosymmetry parameter and the potential energy. A key understanding of the various possible structural changes undergone by these tiny particles is thus developed. The usefulness of the RMD to study nanometre or sub-nanometre size gold clusters is shown.
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